#include <hoel.h>

#define H_OK                0  // No error
#define H_ERROR             1  // Generic error
#define H_ERROR_PARAMS      2  // Error in input parameters
#define H_ERROR_CONNECTION  3  // Error in database connection
#define H_ERROR_DISABLED    4  // Database connection is disabled
#define H_ERROR_QUERY       5  // Error executing query
#define H_ERROR_MEMORY      99 // Error allocating memory

/**
 * free data allocated by hoel functions
 */
void h_free(void * data);

/**
 * h_connect_sqlite
 * Opens a database connection to a sqlite3 db file
 * return pointer to a struct _h_connection * on sucess, NULL on error
 */
struct _h_connection * h_connect_sqlite(const char * db_path);

/**
 * h_connect_mariadb
 * Opens a database connection to a mariadb server
 * return pointer to a struct _h_connection * on success, NULL on error
 */
struct _h_connection * h_connect_mariadb(const char * host, const char * user, const char * passwd, const char * db, const unsigned int port, const char * unix_socket);

/**
 * h_connect_pgsql
 * Opens a database connection to a PostgreSQL server
 * return pointer to a struct _h_connection * on sucess, NULL on error
 */
struct _h_connection * h_connect_pgsql(char * conninfo);

/**
 * Close a database connection
 * return H_OK on success
 */
int h_close_db(struct _h_connection * conn);

/**
 * h_clean_connection
 * free memory allocated by the struct _h_connection
 * return H_OK on success
 */
int h_clean_connection(struct _h_connection * conn);

/**
 * h_escape_string
 * Escapes a string
 * returned value must be h_free'd after use
 */
char * h_escape_string(const struct _h_connection * conn, const char * unsafe);

/**
 * h_escape_string_with_quotes
 * Escapes a string and returns it ready to be inserted in the query
 * returned value must be h_h_free'd after use
 */
char * h_escape_string_with_quotes(const struct _h_connection * conn, const char * unsafe);

/**
 * h_build_where_clause
 * Generates a where clause based on the pattern and the values given
 * @param conn the connection to the database
 * @param pattern the pattern to build the where clause
 * the pattern variables available are the following:
 * - %s: a string value to escape with quotes
 * - %S: a string value to escape without quotes
 * - %c: a string value not to escape with quotes
 * - %C: a string value not to escape without quotes
 * - %d: an integer value in json_int_t format
 * - %f: a double value
 * - %j: a json_t value, the value must be of the type JSON_INTEGER, JSON_REAL or JSON_STRING, string values will be escaped with quotes
 * - %%: the value '%'
 * @return a heap-allocated string
 * returned value must be h_free'd after use
 */
char * h_build_where_clause(const struct _h_connection * conn, const char * pattern, ...);

const char col1[] = "a", col2[] = "b";
json_int_t col3 = 5;
double col4 = 42.3;
char * where_clause = h_build_where_clause("col1=%s AND (col2='S' OR col3=%d) AND col4=%f", col1, col2, col3, col4);
json_t * j_query = json_pack("{sss[ss]s{s{ssss}}}",
                             "table", "table1",
                             "columns",
                               "col1",
                               "col2",
                             "where",
                               " ",
                                 "operator", "raw",
                                 "value", where_clause);
h_free(where_clause);
// Execute j_query

const char col1[] = "a", col2[] = "b";
char * where_clause = h_build_where_clause("col1=%s AND (col2='S' OR col3=%d) AND col4=%f", col1, col2, (json_int_t)5, (double)42.3);

/**
 * h_execute_query
 * Execute a query, set the result structure with the returned values if available
 * if result is NULL, the query is executed but no value will be returned
 * options available
 * H_OPTION_NONE (0): no option
 * H_OPTION_SELECT: Execute a prepare statement (sqlite only)
 * H_OPTION_EXEC: Execute an exec statement (sqlite only)
 * return H_OK on success
 */
int h_execute_query(const struct _h_connection * conn, const char * query, struct _h_result * result, int options);

/**
 * sql result structure
 */
struct _h_result {
  unsigned int nb_rows;
  unsigned int nb_columns;
  struct _h_data ** data;
};

/**
 * sql data container
 */
struct _h_data {
  int type;
  void * t_data;
};

#define HOEL_COL_TYPE_INT    0
#define HOEL_COL_TYPE_DOUBLE 1
#define HOEL_COL_TYPE_TEXT   2
#define HOEL_COL_TYPE_DATE   3
#define HOEL_COL_TYPE_BLOB   4
#define HOEL_COL_TYPE_NULL   5

/**
 * sql value integer type
 */
struct _h_type_int {
  int value;
};

/**
 * sql value double type
 */
struct _h_type_double {
  double value;
};

/**
 * sql value date/time type
 */
struct _h_type_datetime {
  struct tm value;
};

/**
 * sql value string type
 */
struct _h_type_text {
  char * value;
};

/**
 * sql value blob type
 */
struct _h_type_blob {
  size_t length;
  void * value;
};

/**
 * h_clean_result
 * Free all the memory allocated by the struct _h_result
 * return H_OK on success
 */
int h_clean_result(struct _h_result * result);

/**
 * h_clean_data
 * Free memory allocated by the struct _h_data
 * return H_OK on success
 */
int h_clean_data(struct _h_data * data);

/**
 * h_query_last_insert_id
 * return the id of the last inserted value
 * return a pointer to `struct _h_data *` on success, NULL otherwise.
 */
struct _h_data * h_query_last_insert_id(const struct _h_connection * conn);

/**
 * h_query_insert
 * Execute an insert query
 * return H_OK on success
 */
int h_query_insert(const struct _h_connection * conn, const char * query);

/**
 * h_query_update
 * Execute an update query
 * return H_OK on success
 */
int h_query_update(const struct _h_connection * conn, const char * query);

/**
 * h_query_delete
 * Execute an delete query
 * return H_OK on success
 */
int h_query_delete(const struct _h_connection * conn, const char * query);

/**
 * h_execute_query
 * Execute a select query, set the result structure with the returned values
 * return H_OK on success
 */
int h_query_select(const struct _h_connection * conn, const char * query, struct _h_result * result);

/**
 * h_select
 * Execute a select query
 * Uses a json_t * parameter for the query parameters
 * Store the result of the query in j_result if specified. j_result must be decref'd after use
 * Duplicate the generated query in generated_query if specified, must be h_free'd after use
 * return H_OK on success
 */
int h_select(const struct _h_connection * conn, const json_t * j_query, json_t ** j_result, char ** generated_query);

/**
 * h_insert
 * Execute an insert query
 * Uses a json_t * parameter for the query parameters
 * Duplicate the generated query in generated_query if specified, must be h_free'd after use
 * return H_OK on success
 */
int h_insert(const struct _h_connection * conn, const json_t * j_query, char ** generated_query);

/**
 * h_last_insert_id
 * return the id of the last inserted value
 * return a pointer to `json_t *` on success, NULL otherwise.
 * The returned value is of type JSON_INTEGER
 */
json_t * h_last_insert_id(const struct _h_connection * conn);

/**
 * h_update
 * Execute an update query
 * Uses a json_t * parameter for the query parameters
 * Duplicate the generated query in generated_query if specified, must be h_free'd after use
 * return H_OK on success
 */
int h_update(const struct _h_connection * conn, const json_t * j_query, char ** generated_query);

/**
 * h_delete
 * Execute a delete query
 * Uses a json_t * parameter for the query parameters
 * Duplicate the generated query in generated_query if specified, must be h_free'd after use
 * return H_OK on success
 */
int h_delete(const struct _h_connection * conn, const json_t * j_query, char ** generated_query);

/**
 * h_last_insert_id
 * return the id of the last inserted value
 * return a pointer to `json_t *` on success, NULL otherwise.
 * The returned value is of type JSON_INTEGER
 */
json_t * h_last_insert_id(const struct _h_connection * conn);